# 封装数据库工具类
class DBUtil(object):
    @classmethod
    def __get_conn(cls):
        pass

    @classmethod
    def __close_conn(cls):
        pass

    # 常用方法：查询一条
    @classmethod
    def select_one(cls, sql):
        pass

    # 常用方法：增删改
    @classmethod
    def uid_db(cls, sql):
        pass
